I'm running Zee and they're without a doubt the best I have used. As has been stated, for some reason they are a bit less grabby than XT/XTR but have tons more top end power, really good for when you're tired or have bad arm pump.

Cheap, lightish, stupidly powerful and easy to get cheap pads for (I use Superstar sintered in a pack of 4 for £22). Interested to try the new SRAM Guide up against them for comparison, but they'd have to be incredible to make me change.